[ns] Attacker/Spoofer in NS2

Hi,

I want to simulate a scenario with dumbbell topology (2 end nodes(say n0,
n1) and 2 routers(r0, r1)). One of the router (say r1) will act as a packet
spoofer. A FullTcp connection (n0-n1) will be set up between two end nodes
and r1 will check particular ACK packets and will create duplicate copies
of it (to be sent to source). Is it possible to simulate such scenario in
ns2?? Any help is appreciated.

Thanks,

Ashish Bhandari